$\"\"$

\

The functions are $\"\"$ and $\"\"$ .

\

Consider $\"\"$ .

\

$\"\"$

\

Apply formula : $\"\"$ .

\

$\"\"$

\

Pythagorean identity : $\"\"$ .

\

$\"\"$

\

$\"\"$ .

\

$\"\"$

\

The functions $\"\"$ and $\"\"$ are identically equal.